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Biomedical subjects

A Reigstad

Publications and source records attributed to A Reigstad.

At least 19 recordsLinked to original sources
PubMed2003

Tissue reactions adjacent to well-fixed hydroxyapatite-coated acetabular cups. Histopathology of ten specimens retrieved at reoperation after 0.3 to 5.8 years.

Ten acetabular cups coated with hydroxyapatite (HA) had originally been inserted in five primary and five revision total hip replacements. The thickness of the HA was 155 +/- 35 microm. The cups, which were well-fixed, were retrieved, with their adherent tissue, at reoperation after 0.3 to 5.8 years because of infection (five hips), wear of polyethylene (three hips), and instability (two hips). Undecalcified sections showed a direct contact between bone and osteoid-like tissue which had formed directly onto the HA coating. The area within the threads and their mirror images, as well as the implant-tissue interfaces consisted of similar amounts of bone and soft tissue. Degradation of HA was seen in all hips. The mean thickness of the remaining HA coating was 97 microm (95% CI 94 to 101). The metal interface comprised 66% HA. The HA-tissue interface contained more bone than soft tissue (p = 0.001), whereas the metal-tissue interface included more soft tissue than bone (p = 0.019). Soft tissue at the implant interface and poor replacement of HA by bone may interfere with long-term fixation.

Acetabulum↗
PubMed2001

Vital staining of bone in stable, retrieved femoral surface replacement prostheses: a microscopic study of undecalcified ground sections.

We used vital staining with tetracycline to detect viability of bone at the bone-cement interface in 11 stable ICLH femoral surface replacement prostheses that were retrieved at revision surgery for acetabular loosening. The resected femoral heads were processed for undecalcified ground sections with the prostheses in situ. All sections showed direct bone-to-cement contacts. Bone in direct contact with or close to the cement sometimes showed an abnormal staining, indicating that the bone was not fully mineralized. Areas with fluorescence were observed within all femoral heads but never in direct bone-to-cement contact. From this study, we conclude that the mechanical stability of these cemented femoral surface replacement prostheses depends mainly on the original bone present at the time of primary operation.

Acetabulum↗
PubMed1999

Assessment of nutritional status in patients with rheumatoid arthritis and osteoarthritis undergoing joint replacement surgery.

OBJECTIVE: To evaluate pre- and postoperative nutritional status in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). METHODS: Preoperative dietary intake was assessed by a food frequency questionnaire, and postoperative dietary intake by food records. Anthropometric and laboratory measurements were assessed 1 day before and 10 days after surgery. Disease activity and acute response to surgery were assessed by erythrocyte sedimentation rate and G-reactive protein. RESULTS: The dietary intake was similar in the two groups preoperatively. Energy, protein, and fluid intake was significantly higher in the RA group postoperatively. There was a significant reduction in the concentration of hemoglobin, albumin, total protein, and ferritin in the OA group after surgery, whereas only hemoglobin concentration was reduced in the RA group. CONCLUSION: Preoperative nutritional status in the RA group was reduced as compared with preoperative nutritional status in the OA group. However, nutritional status in the RA group was less affected after joint replacement surgery compared with nutritional status in the OA group.

Adult↗
PubMed1999

Total hip replacement with an entirely hydroxyapatite-coated prosthesis: 5 years' follow-up of 94 consecutive hips.

The first 100 consecutive entirely hydroxyapatite (HA)-coated hip arthroplasties in 86 patients (mean age, 56.2 years [range, 32-73 years]; female-to-male ratio, 75:25) were followed with standardized radiographs annually up to 5 years. All components developed 100% intimate bone-implant contact, being gradually reduced to 99.5%+/-3.8% by 2 partial periacetabular lines and on the femoral side to 94.0%+/-6.1% and 96.5%+/-5.2% in the frontal and lateral planes by lines along 75 stems, mostly in zones 1 and 8. Bone formation took place adjacent to the prostheses regularly, with gap filling and comprehensive periprosthetic bone remodeling, stabilizing at 3 years. No adverse stress shielding was found. The clinical results were excellent without thigh pain. We believe that all components were bonded directly to bone, promoted by the reliable primary fixation and the osteoconductive effect of HA.

Adult↗
PubMed1999

Polyethylene wear, osteolysis and acetabular loosening with an HA-coated hip prosthesis. A follow-up of 94 consecutive arthroplasties.

We have followed up for a period of seven to nine years 100 consecutive arthroplasties of the hip in which an entirely HA-coated implant had been used. The clinical results were excellent and bony incorporation was extensive in all components. No stem became loose or subsided but five cups were revised because of loosening after 3.8 to 5.5 years, having functioned painlessly and shown radiological ingrowth. Revision procedures because of excessive polyethylene wear have been performed on 18 hips and are planned for six more. Two eroded metal backings with worn-through polyethylene were exchanged; six hips showed metallosis without polyethylene wear-through. There were two cases of granulomatous cysts in the groin and 66 hips had osteolysis located periarticularly, in the greater trochanter or in the acetabulum.

Acetabulum↗
PubMed1998

Surface structure of retrieved ICLH femoral cups.

We characterized the surface structure of 21 retrieved femoral ICLH cups, as an indirect measure of surface damage, with an optical scanner specially developed for surface roughness measurements. 3 unused cups were measured and served as controls. The mean insertion time was 10 (5-15) years. 5 areas on each cup were measured, 1 on the top and 4 at the edge. The mean value of 3 different, commonly used, surface roughness parameters was calculated for the edge measurements. We found no correlation between the surface topography and clinical patient data such as age, body-weight, head-shaft angle, implantation time and wear of the polyethylene socket.

Aged↗
PubMed1998

Polyethylene wear with an entirely HA-coated total hip replacement: 79 hips followed for 5 years.

We measured the eccentricity of the femoral head in the metal backing annually during 5 years in 79 consecutive total hip replacements (73 patients). The mean age of the patients was 57 (32-73) years and the female/male ratio 63/22. The prostheses were entirely coated with hydroxyapatite. Modular 32 mm stainless steel heads and hemispherical, self-tapping screw cups with polyethylene liners were used. We found accelerating eccentricity throughout the observation period. The mean eccentricity at 5 years was 0.71 mm (95% CI 0.53-0.90), resulting in a mean eccentricity rate of 0.14 mm (0.11-0.18) per year. The 5-year eccentricity was 0.5 mm or less in 45 hips and more than 1.5 mm in 13 hips, 2 in the latter group apparently having worn through the polyethylene liner. The true wear may be twice as great. The use of 32 mm stainless steel heads and thin polyethylene inlays may have aggravated the wear problems. These HA-coated prostheses must all be checked regularly, so that cases with excessive polyethylene wear can be reoperated on before wear-through of the liner.

Adult↗
PubMed1996

[Free vascular grafts in reconstructions in the head and neck region].

Since 1989, 40 free-tissue grafts were used in 39 patients to repair defects following major head and neck ablative surgery (n = 32) and for reconstruction of the mandible because of osteoradionecrosis or trauma (n = 7). The radial forearm flap was used in 17 patients (five including a segment of radius), the lateral arm flap in seven, fibula in five and a segment of ileum for restoration of the hypopharynx in 11 cases. Three radial forearm flaps and the bone in one lateral arm flap failed. Better functional and cosmetic results seem to be obtained with free flaps than with other reconstructive techniques.

Craniocerebral Trauma↗
PubMed1995

Stem fracture with the Exeter prosthesis. 3 of 27 hips followed for 10 years.

We report the results of a 9-11-year clinical and radiographic follow-up of 27 Exeter prostheses in which cement pressurizing technique was employed. 3 stems fractured and 3 other stems and 1 cup underwent aseptic loosening. The remaining prostheses had satisfactory clinical and radiographic results. Stem subsidence was seen only as part of a loosening process. We suspect that the pronounced taper design is responsible for the poor results. While the slender and weak distal end is fixed in a thick cement mantle, the wide proximal part allows only a thin cement layer, easily subjected to mechanical disintegration. Proximal debonding increases both the stress on the distal part of the stem and the distal bone-cement interface shear stress. Hence, we believe that the same process underlies both the loosenings and the stem fractures. The presently employed Exeter stem is manufactured from the stronger Orthinox steel, which may diminish the risk for fracture, but it has retained the extreme taper design. It is not likely that a polished surface or improved cementing will prevent stem fracture. Therefore, one should still be concerned about late fractures of the Exeter stem.

Aged↗
PubMed1994

Free flaps in the reconstruction of foot injury. 4 (1-7) year follow-up of 24 cases.

We reconstructed in 24 patients, traumatic tissue loss in the foot with 10 lateral arm flaps and 14 scapular flaps. The mean follow-up was 4 (1-7) years. There was 1 flap loss, and 1 patient was amputated because of septic ankle arthrodesis. Healing with stable skin and scar was achieved in the remaining patients. Only patients with additional serious skeletal injury had reduced walking ability.

Adolescent↗
PubMed1993

[Standardization, control and approval of surgical implants in Europe].

The "new approach" policy limits the European Community legislative harmonization to adopting essential safety requirements which medical devices brought on the market will have to meet, and thereafter obtaining free trade in the European market. A set of harmonized standards will explain in detail what the essential requirements mean in practice. Therefore, the work being done on standards for surgical implants by the European Committee for Standardization (CEN) is indispensable. The impact of the "New Approach" on the Norwegian legislation is discussed, and it is concluded that the Committee for Single-Use Medical Devices, which registers all surgical implants prior to marketing in Norway, will have to close down in 1995.

Biocompatible Materials↗
PubMed1993

[Treatment routines of flexor tendon injuries. Results of a questionnaire study].

A questionnaire was distributed to the surgical departments of all Norwegian hospitals, asking about the routines for treating flexor tendon injuries in 1990. The response rate was 95.5%. Some of the smaller hospitals did their own flexor tendon surgery, but referred patients with a complex injury to a hospital with better trained hand surgeons. In 1990, a total of 573 flexor tendon repairs were carried out in Norwegian hospitals. After surgery, all patients had a cast or a brace for a period ranging from three to six weeks. Most of the hospitals used dynamic traction and had a programme for training the patient, which was supervised by a hand therapist. Active flexion was allowed from two to eight weeks after the operation. We recommend referral of all flexor tendon injuries in zone II to a surgical unit with trained hand surgeons. After surgery, a programme including dynamic traction and training supervised by the surgeon and a hand therapist should be compulsory.

Hand Injuries↗
PubMed1993

Cross thumb transfer.

Thumb reconstruction following amputation was accomplished by microvascular transfer of the thumb from the contralateral paralyzed hand in two cases. The appearance and function of the transferred thumbs were excellent and no problem was seen in the donor hand.

Adult↗
PubMed1993

A qualitative and quantitative study of retrieved femoral heads in three different types of resurface hip arthroplasties.

Tissue reactions and percentage of mineralized bone in three different types of retrieved femoral head hip resurface prostheses were studied in undecalcified ground sections without removing the metal. All of the prostheses demonstrated soft tissue between the cement-implant and bone. There were some areas without soft tissue between bone and cement. This bone was often not normally stained, indicating a disturbed mineralization. The soft tissue layer in the cemented prostheses was observed in different stages of necrosis, while the uncemented prostheses demonstrated a thick collagen membrane. One of the cemented groups demonstrated a gradual decrease of mineralized bone towards the cement. The uncemented implants revealed normal bone qualitatively and quantitatively when the bone bordering the prosthesis was excluded. Too high interfacial stresses were probably a major failure mechanism, especially in the rapidly failed noncemented prostheses. Negative long-term effects of the cement on the bone may have contributed to failure in the cemented resurface arthroplasties.

Adult↗
PubMed1993

Femoral remodeling after arthroplasty of the hip. Prospective randomized 5-year comparison of 120 cemented/uncemented cases of arthrosis.

We compared radiographically the femurs for 5 years after cemented (Landos Titane) and uncemented (Zweymüller/Endler) hip arthroplasty (THA) for coxarthrosis in 120 patients. The bone changes followed a characteristic time-course with rapid initial remodeling and almost no further changes after 3-4 years. No association between bone changes and clinical results was found. The groups did not differ in bone atrophy and ectopic bone formation, whereas the incidence of distal cortical hypertrophy and proximal radio-opaque double line was higher around uncemented stems. The age and body weight of the patients and the stem size did not affect the bone changes, but women with uncemented stems developed more bone atrophy than did men.

Aged↗